The present disclosure herein relates to an optical amplifier, and more particularly, to a pulse width stretcher that stretches the pulse width of a pulse laser beam, and a chirped pulse amplifier including the same.
In the mid-1980s, there was an important advance of optical technology that overcomes the output power limit of a pulse laser beam according to the damage threshold of a gain medium. That is a chirped pulse amplification technique. The chirped pulse amplification technique may provide a pulse laser beam having output power significantly higher than a general pulse amplification technique. A conventional chirped pulse amplifier may generate a pulse laser beam having maximum output power lower than or equal to about 1 GW. The chirped pulse amplifier may control the pulse width of a pulse laser beam to minimize the effect of the damage threshold of an optical medium. Thus, the chirped pulse amplifier may generate a pulse laser beam having maximum output power equal to higher than about 1 TW.